/*
 * $Id: StringValues.java 3927 2011-02-22 16:34:11Z kleopatra $
 *
 * Copyright 2008 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
package org.jdesktop.swingx.renderer;

import java.io.File;
import java.text.DateFormat;
import java.text.NumberFormat;
import java.util.Locale;

import javax.swing.filechooser.FileSystemView;
import javax.swing.plaf.UIResource;

import org.jdesktop.swingx.util.Contract;

/**
 * A collection of common {@code StringValue} implementations.
 * 
 * @author Karl George Schaefer
 * @author Jeanette Winzenburg
 */
public final class StringValues {
	/**
	 * A {@code StringValue} that always presents an empty string.
	 */
	@SuppressWarnings("serial")
	public final static StringValue EMPTY = new StringValue() {
		@Override
		public String getString(Object value) {
			return "";
		}
	};

	/**
	 * A {@code StringValue} that presents a {@link Object#toString() toString}
	 * value for the given object. If the value passed is {@code null}, this has
	 * the same effect as {@link StringValues#EMPTY}.
	 */
	@SuppressWarnings("serial")
	public final static StringValue TO_STRING = new StringValue() {
		@Override
		public String getString(Object value) {
			return (value != null) ? value.toString() : StringValues.EMPTY.getString(value);
		}
	};

	/**
	 * A {@code StringValue} that presents the current L&F display name for a
	 * given file. If the value passed to {@code FILE_NAME} is not a
	 * {@link File}, this has the same effect as {@link StringValues#TO_STRING}.
	 */
	@SuppressWarnings("serial")
	public static final StringValue FILE_NAME = new StringValue() {
		@Override
		public String getString(Object value) {
			if (value instanceof File) {
				FileSystemView fsv = FileSystemView.getFileSystemView();

				return fsv.getSystemDisplayName((File) value);
			}

			return StringValues.TO_STRING.getString(value);
		}
	};

	/**
	 * A {@code StringValue} that presents the current L&F type name for a given
	 * file. If the value passed to {@code FILE_TYPE} is not a {@link File},
	 * this has the same effect as {@link StringValues#TO_STRING}.
	 */
	@SuppressWarnings("serial")
	public static final StringValue FILE_TYPE = new StringValue() {
		@Override
		public String getString(Object value) {
			if (value instanceof File) {
				FileSystemView fsv = FileSystemView.getFileSystemView();

				return fsv.getSystemTypeDescription((File) value);
			}

			return StringValues.TO_STRING.getString(value);
		}
	};

	/** keep track of default locale. */
	private static Locale defaultLocale;

	/**
	 * Returns a boolean to indicate if the default Locale has changed. Updates
	 * internal state to keep track of the default Locale.
	 * 
	 * @return true if the default Locale has changed.
	 */
	private static boolean localeChanged() {
		boolean changed = !Locale.getDefault().equals(defaultLocale);
		if (changed) {
			defaultLocale = Locale.getDefault();
		}
		return changed;
	}

	/**
	 * Default converter for <code>Date</code> types. Uses the default format as
	 * returned from <code>DateFormat</code>.
	 */
	@SuppressWarnings("serial")
	public final static FormatStringValue DATE_TO_STRING = new FormatStringValue() {

		/**
		 * {@inheritDoc}
		 */
		@Override
		public String getString(Object value) {
			if (format == null || localeChanged()) {
				format = DateFormat.getDateInstance();
			}
			return super.getString(value);
		}

	};

	/**
	 * Default converter for <code>Number</code> types. Uses the default format
	 * as returned from <code>NumberFormat</code>.
	 */
	@SuppressWarnings("serial")
	public final static FormatStringValue NUMBER_TO_STRING = new FormatStringValue() {

		/**
		 * {@inheritDoc}
		 */
		@Override
		public String getString(Object value) {
			if (format == null || localeChanged()) {
				format = NumberFormat.getNumberInstance();
			}
			return super.getString(value);
		}

	};

	public static final StringValue TO_STRING_UI = new StringValueUIResource(StringValues.TO_STRING);
	public static final StringValue EMPTY_UI = new StringValueUIResource(StringValues.EMPTY);

	/**
	 * StringValue wrapper of type UIResource to tag LAF installed converters.
	 * 
	 * @author Jeanette Winzenburg, Berlin
	 */
	public static class StringValueUIResource implements StringValue, UIResource {

		private StringValue delegate;

		public StringValueUIResource(StringValue toString) {
			Contract.asNotNull(toString, "delegate StringValue must not be null");
			this.delegate = toString;
		}

		@Override
		public String getString(Object value) {
			return delegate.getString(value);
		}

	}

	private StringValues() {
		// does nothing
	}
}
